How Much Protein to Build Muscle Per Day? The Science-Based Answer

Julius Granlund

Julius Granlund

M.Sc. in Exercise Science (Exercise Physiology), Psychologist

Published:

Summary: To build muscle mass, men should aim for roughly 1.6–2.2 grams of protein per kilogram of body weight per day. For women, a slightly lower target works well, about 10% less, or around 1.44–1.98 g/kg. For example, an 80 kg man would need roughly 128–176 grams of protein a day, while a 60 kg woman would need about 86–119 g per day. For most lifters, a daily protein intake of at least 1.6 g/kg is enough to maximize muscle growth. Beyond that the returns shrink, though some researchers put the optimum closer to 2.0 g/kg. If you want a conservative target, 2.0 g/kg is a solid recommendation, especially during weight loss, when the goal is to lose fat while preserving muscle mass. It's also worth spreading protein evenly across the day, roughly every 3–5 hours, or across 3–6 meals a day that each contain enough of it. The Finnish AI training app AITOFIT handles the training side, while this article explains how to match it with your nutrition.

This article looks at the research on how much protein you need to maximize your results: why adequate protein intake matters, how many grams you need per day, when to eat protein, and the most common protein-related mistakes.

How much protein per day do you need for muscle growth?

The recommended protein intake for anyone aiming to build muscle is roughly 1.6–2.2 g of protein per kilogram of body weight per day. At least 1.6 g/kg is enough to maximize muscle growth for the vast majority of lifters. Women typically need a little less because protein requirements scale with lean body mass, and women carry, on average, about 10% less of it.

The recommendation rests on several recent meta-analyses. The analysis by Morton et al. (2018) pooled 49 studies and over 1,800 participants and identified a so-called breakpoint at 1.62 g/kg: the point beyond which, according to that study, additional protein no longer meaningfully increased lean mass on average.

The exact optimum, however, is a matter of genuine scientific debate. In 2026, a panel of leading protein researchers (Kanter et al.) likewise concluded that the benefits plateau in most cases around 1.6 g/kg. On the other hand, some researchers argue that the optimum is higher, closer to 2.0 g/kg, because Morton's 1.6 g/kg finding wasn't statistically significant, and its confidence interval stretched all the way to 2.2 g/kg. Either way, the practical takeaway is the same in both camps: aim for at least 1.6 g/kg, and if you want to be sure, 2.0–2.2 g/kg is an effective level. In practice, staying within this range is a sensible way to support your training.

Protein needs by body weight: table for men

Body weight

Enough (1.6 g/kg)

To be safe (2.2 g/kg)

60 kg

96 g

132 g

70 kg

112 g

154 g

80 kg

128 g

176 g

90 kg

144 g

198 g

100 kg

160 g

220 g

Practical rule of thumb: 1.6 g/kg is enough for most men to maximize muscle growth, and 2.2 g/kg is a reasonable higher target. If you want more flexibility in your diet, even 1.2–1.5 g/kg delivers the bulk of the possible results.

Protein needs by body weight: table for women

Using the 10% lower range for women (1.44–1.98 g/kg), the table looks like this:

Body weight

Enough (1.44 g/kg)

To be safe (1.98 g/kg)

50 kg

72 g

99 g

60 kg

86 g

119 g

70 kg

101 g

139 g

80 kg

115 g

158 g

90 kg

130 g

178 g

100 kg

144 g

198 g

Is 1.6 g/kg enough, or do you need more?

This is a good example of how science is rarely as clear-cut as social media can make it seem. There's a genuine scientific debate about the optimal amount of protein, and researchers broadly fall into two camps:

View 1: 1.6 g/kg is enough for most people. In 2026, a panel of leading protein researchers (Kanter et al.) concluded that the benefits plateau in most cases around 1.6 g/kg. That's also the conclusion of the original Morton meta-analysis. On this view, eating more than 1.6 g/kg isn't harmful, but for most people it no longer adds meaningful muscle.

View 2: the ideal protein intake may be closer to 2.0 g/kg. Some researchers point out that Morton's breakpoint (1.62 g/kg) wasn't statistically significant, and its confidence interval reached all the way to 2.2 g/kg. When you look specifically at people who already train, a higher protein intake above 1.6 g/kg often appears to produce additional growth. On this view, a safer target is 2.0–2.2 g/kg.

What does this mean in practice? Fortunately, the disagreement doesn't matter much day to day, because both camps agree on what counts:

  • 1.6 g/kg is a solid baseline: at this level you'll get at least the bulk of the results.

  • 2.0–2.2 g/kg isn't harmful: if you want to aim for the upper end of the evidence-based range, this is still a sensible, well-founded level.

  • Above 2.2 g/kg probably brings no further benefit for muscle growth, crowds out carbs and fats, and requires a very high protein intake each day.

  • Even 1.2–1.5 g/kg is enough for most of the results, if you want flexibility in your diet.

  • Note: If your goal is to lose weight while maintaining or building muscle at the same time, it's better to set your protein intake closer to the 2.0–2.2 g/kg target. This is to minimize muscle loss as the weight comes off.

In other words, don't agonize over hitting an exact gram target. Land in the 1.6–2.2 g/kg range, spread your protein fairly evenly across the day, and you've covered this part well.

Why is protein important for muscle growth?

Muscle tissue and muscle function depend on a constant cycle of muscle protein synthesis and muscle protein breakdown. Dietary protein provides amino acids, including the essential amino acids the human body cannot make itself. Strength training helps stimulate muscle protein synthesis. When you also get enough protein, your body has the raw materials it needs for muscle building and muscle recovery. Over the long run, muscle mass grows when muscle protein synthesis exceeds muscle breakdown.

Protein plays two important roles in muscle growth:

1. Building material: Muscles, tendons and other tissues are built from protein. Insufficient protein intake limits muscle growth and recovery, even if your training is otherwise optimal.

2. Trigger for muscle protein synthesis
The amino acids in protein, particularly leucine, help stimulate muscle protein synthesis, the muscle-building process. While your total daily protein intake is the most important factor, spreading it across several protein-rich meals during the day can support muscle growth even further.

When should you eat protein?

Based on the research, protein timing matters less than people often think. What matters most is getting enough protein over the whole day. Although daily protein is the most important factor, it can still make sense to spread protein across 3–6 protein-rich meals. This may offer a small added benefit for muscle growth, though beyond three meals there doesn't seem to be any further gain from dividing your intake into more. The right number of meals therefore comes down to what fits your daily life.

The most useful times to include protein:

  1. In the morning: After the overnight fast, your body's amino acid stores are at their lowest.

  2. After training: Muscle protein synthesis increases, and the body needs building materials.

  3. In the evening: During the night your body repairs and builds tissue for a long stretch without food.

As a rough guide, around 25–50 grams of protein per meal is a sufficient amount for many people, depending on your size and your total goal for the day.

Can you eat too much protein?

For a healthy person, even a high protein diet is not dangerous according to current research. Common concerns that too much protein damages the kidneys or bones have largely been debunked in studies of healthy people. The more relevant question is when extra protein stops providing additional benefit for muscle growth.

The benefits most likely plateau somewhere between 1.6 and 2.2 g/kg. Once total intake goes beyond this range, extra protein brings two practical downsides:

1. It crowds out carbs and healthy fats. The energy from surplus protein could instead come from carbohydrates and healthy fats that help keep a balanced diet and support training performance.

2. It takes up room on your plate and adds to the cost of your diet. A very high protein intake can get expensive and is also filling, which can make it harder to hit enough total energy for muscle growth.

Where should you get your protein?

Good protein sources include lean meats, fish, dairy products, eggs, soy protein and other plant proteins. Some common examples are listed below:

Source

Protein / 100 g

Chicken breast

23 g

Ground beef (10% fat)

20 g

Salmon

20 g

Cottage cheese

12 g

Eggs (2)

13 g

Quark

10 g

Tofu

12 g

Soy mince (dry)

50 g

Whey protein powder (30 g serving)

24 g

Protein supplements aren't essential, but protein shakes, protein powder and protein bars can be convenient ways to top up your intake, especially after training or on busy days. Whey protein powder is one common option, while plant-based protein supplements work well too. They aren't "better" than protein from food. They are simply practical ways to increase your daily protein intake.

The most common protein mistakes

Mistake 1: Over-optimizing

Plenty of people get stuck wondering whether the right number is 1.6, 2.0 or 2.2 g/kg. Even the researchers disagree on this. Fortunately, it doesn't matter much in practice. Stay within the 1.6–2.2 g/kg range and you're in a good place. Besides, hitting an exact number every single day would be very hard. As a woman, aim for at least 1.44 grams per kilogram of body weight per day, and as a man at least 1.6 g/kg. What matters more than the decimals is that your intake is sufficient and, ideally, fairly even.

Mistake 2: Forgetting protein on lighter days

On rest days your protein needs are essentially the same as on training days.

Mistake 3: Optimizing protein without optimizing training

Protein provides the building material, but without strength training that provides a sufficient stimulus, there is little reason for the body to build more muscle mass. Optimal protein intake on a mediocre training program still produces mediocre results. This applies just as much to a beginner's gym routine as it does to an advanced one.

Mistake 4: Too much protein

This is common because protein gets so much attention on social media.

Protein + optimized training = results

Protein intake is only one part of the equation when working toward a healthier, more muscular or more toned body, depending on your goal. Put simply, muscle growth requires two things: enough building material (protein) and a properly sized stimulus (training).

On the training side, a good workout program means individualized volume (5–20 sets per muscle group per week), the right weights and reps, progressive overload from one session to the next, and tracking your recovery. Managing all of this manually takes time, which is exactly what an AI workout program is built for.

AITOFIT is a Finnish AI training app developed by exercise scientists at the University of Jyväskylä. It automatically manages your weights, reps, set counts and program progression. When the app handles the training side and you manage your protein intake using the guidance in this article, both sides of the equation are covered. More than 5,000 users have rated the app 4.9/5.

You can try AITOFIT free for 9 days, no credit card required.

Frequently asked questions

How much protein per day do you need for muscle growth?

For muscle growth, aim for roughly 1.6–2.2 g of protein per kilogram of body weight per day. At least 1.6 g/kg is enough to maximize growth for most people, and some researchers recommend up to 2.0–2.2 g/kg to be safe. An 80 kg person, for example, would target about 128–176 grams a day. Even 1.2–1.5 g/kg is enough for most of the possible results if you want more flexibility in your diet.

Is 100 grams of protein a day enough?

It depends on your weight and your goal. For a 60 kg person, 100 g (1.67 g/kg) is a good level for muscle growth. For an 85 kg person it falls below the recommendation (1.18 g/kg), which means some potential muscle gain may be left on the table. An 85 kg person aiming to gain muscle would benefit from targeting at least 135 grams (1.6 g/kg).

Do you have to eat protein right after training?

You don't have to eat immediately, but a post-workout meal with protein is one of the most important of the day. According to research, the "anabolic window" is several hours, not 30 minutes. What matters most is your total intake for the day and spreading it evenly.

Are protein supplements essential?

No. Protein supplements are a practical way to top up your intake, but you can get all the protein you need from regular food. That said, whey protein is cheap and convenient, especially after training.

Can too much protein be harmful?

For a healthy person, even a high protein intake (e.g. 2.5 g/kg) is not dangerous. Contrary to what's sometimes claimed, a high protein intake doesn't damage healthy people's kidneys or weaken their bones. For muscle growth, though, the benefits plateau somewhere around 1.6–2.2 g/kg, so intake beyond that usually doesn't add further growth and crowds out carbs that could support training performance.

How much protein do you need when losing weight?

During a weight-loss phase your protein needs are slightly higher, because a caloric deficit can increase muscle breakdown. Research suggests aiming for the upper end of the range, roughly 1.8–2.2 g/kg, to maintain muscle mass and preserve muscle during a deficit. The single most important factor for preserving muscle, however, is resistance training. Protein supports it; it doesn't replace it. A higher protein intake can be especially useful for already-lean lifters trying to lose fat while maintaining muscle and keeping body fat moving in the desired direction.

Is plant protein as good as animal protein?

Plant proteins work well when your total intake is adequate and your sources are varied. Complete proteins contain all nine essential amino acids, while incomplete proteins are lower in one or more of them. Animal proteins are generally complete proteins, while soy protein is one of the complete protein sources available in a plant-based diet. Not all protein from plants has the same amino acid profile, so combining complete and incomplete proteins can help cover your needs. Research shows a plant-based diet can produce the same muscle growth as a mixed diet when you get sufficient protein (at least 1.6 g/kg) and the diet isn't short on any essential amino acid. On a plant-based diet, it's worth aiming for the upper end of the range and combining different protein sources, because most plant proteins have a less complete amino acid profile. As protein intake rises, though, the importance of source quality decreases.

Summary: how much protein per day?

The answer: roughly 1.6–2.2 g per kilogram of body weight per day, spread evenly at 3–5 hour intervals.

Remember these:

  1. 1.6 g/kg is enough for most people to maximize muscle growth

  2. 2.0–2.2 g/kg is a reasonable higher target

  3. Women can typically get by with a slightly lower level

  4. Spread your intake across 4–5 meals, each with a protein source

  5. Include protein in the morning, the post-workout window and the evening

  6. When losing weight, aim for the upper end of the range to preserve muscle mass

  7. Above 2.2 g/kg probably adds no extra benefit; leave room for carbs instead

  8. Protein works best alongside well-designed training

Once your nutrition is in place, make sure your training is too. Try AITOFIT free for 9 days. The app was developed by exercise scientists at the University of Jyväskylä and adjusts your strength training to match your progress.

Sources: Kanter et al. (2026), Examining Widely Held Propositions on Human Dietary Protein Needs and Benefits: A Critical Review. Morton et al. (2018), A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. Tagawa et al. (2020), Dose–response relationship between protein intake and muscle mass increase. Nutrition Reviews. Nunes et al. (2022), Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults. Journal of Cachexia, Sarcopenia and Muscle. Hevia-Larraín et al. (2021), High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations. Sports Medicine. Helms et al. (2018), The Muscle and Strength Pyramid: Nutrition. Ilander, O. et al. (2021), Liikuntaravitsemus 3.0 (Sports Nutrition 3.0). VK-Kustannus.

Author: Julius Granlund, M.Sc. in Exercise Science (Exercise Physiology), University of Jyväskylä | Reviewed by: Tapio Tulenheimo, M.Sc. in Exercise Science (Exercise Physiology), University of Jyväskylä